Moldable styrene-maleic anhydride/polybutylene terephthalate composition

Abstract

Moldable blends of styrene/maleic anhydride copolymer, polybutylene terephthalate ester, and styrene-maleimide copolymer having pendant carboxyl or hydroxyl groups are provided. In one embodimnent, the incorporation of the styrene-maleimide copolymer results in a composition having co-continuous phases. The compositions of this invention facilitate the production of blow molded articles.

What is claimed is: 
     
       1. A moldable composition comprising: (a) a styrene-maleic anhydride copolymer;   (b) a polybutylene terephthalate ester; and   (c) a styrene-maleimide copolymer having pendant carboxyl or hydroxyl groups, wherein the weight ratio of copolymer (a) to polyester (b) is from about 90:10 to about 10:90, and the amount of copolymer (c) in parts by weight is from about 1 to about 20 parts per each 100 parts by weight of total (a) +(b) +(c).   
     
     
       2. The composition of claim 1 in which said styrene-maleic anhydride copolymer contains from about 1 to about 25 weight percent maleic anhydride. 
     
     
       3. The composition of claim 1 in which said styrene-maleic anhydride copolymer is an impact modified styrene-maleic anhydride copolymer. 
     
     
       4. The composition of claim 3 in which said styrene-maleic anhydride copolymer is impact modified by the incorporation of a rubber. 
     
     
       5. The composition of claim 1 in which said weight ratio of copolymer (a) to polyester (b) is from about 60:40 to about 40:60. 
     
     
       6. The composition of claim 1 in which said amount of copolymer (c) in parts by weight is from about 8 to about 12 per each 100 parts by weight of total (a)+(b)+(c). 
     
     
       7. The composition of claim 1 in which said styrene-maleic anhydride copolymer has a number average molecular weight within the range of from about 50,000 to about 300,000. 
     
     
       8. A moldable composition comprising: (a) a styrene-maleic anhydride copolymer having a number average molecular weight within the range of from about 50,000 to about 300,000;   (b) a polybutylene terephthalate ester; and   (c) a styrene-maleimide copolymer having pendant carboxyl or hydroxyl groups, wherein the weight ratio of copolymer (a) to polyester (b) is from about 60:40 to about 40:60, and the amount of copolymer (c) in parts by weight is from about 8 to about 12 parts per each 100 parts by Weight of total (a)+(b)+(c), and wherein copolymer (a) and polyester (b) are present in the composition as co-continuous phases.   
     
     
       9. The composition of claim 8 in which said styrene-maleic anhydride copolymer is an impact modified styrene-maleic anhydride copolymer. 
     
     
       10. A molded article produced by molding a composition comprising: (a) a styrene-maleic anhydride copolymer;   (b) a polybutylene terephthalate ester; and   (c) a styrene-maleimide copolymer having pendant carboxyl or hydroxyl groups, wherein the weight ratio of copolymer (a) to polyester (b) is from about 90:10 to about 10:90, and the amount of copolymer (c) in parts by weight is from about 1 to about 20 parts per each 100 parts of total (a)+(b)+(c).   
     
     
       11. The molded article of claim 10 being a blow molded article produced by blow molding said, composition. 
     
     
       12. The molded article of claim 10 in which said styrene-maleic anhydride copolymer contains from about 1 to about 25 weight percent maleic anhydride. 
     
     
       13. The molded article of claim 10 in which said styrene-maleic anhydride copolymer is an impact modified styrene-maleic anhydride copolymer. 
     
     
       14. The molded article of claim 13 in which said styrene-maleic anhydride copolymer is impact modified by the incorporation of a rubber. 
     
     
       15. The molded article of claim 10 in which said weight ratio of copolymer (a) to polyester (b) is from about 60:40 to about 40:60. 
     
     
       16. The molded article of claim 10 in which said copolymer (c) in parts by weight is from about 8 to about 12 per each 100 parts by weight of total (a)+(b)+(c). 
     
     
       17. The molded article of claim 10 in which said anhydride copolymer has a number average molecular weight within the range of from about 50,000 to about 300,000. 
     
     
       18. A molded article produced by molding a composition having two co-continuous phases comprising: (a) a styrene-maleic anhydride copolymer having a number average molecular weight within the range of from about 50,000 to about 300,000;   (b) a polybutylene terephthalate ester; and   (c) a styrene-maleimide copolymer having pendant carboxyl or hydroxyl groups, wherein the weight ratio of copolymer (a) to polyester (b) is from about 60:40 to about 40:60, and the amount of copolymer (c) in parts by weight is from about 8 to about 12 parts per each 100 parts by weight of total (a)+(b)+(c), and wherein copolymer (a) and polyester (b) are present in the composition as co-continuous phases.   
     
     
       19. The article of claim 18 being a blow molded article produced by blow molding said composition. 
     
     
       20. A molded composition comprising a first continuous phase, a second continuous phase, and an interface, wherein the first continuous phase comprises styrene-maleic anhydride copolymer, the second continuous phase comprises polybutylene terephthalate, and the interface comprises a styrene-maleimide copolymer having pendant carboxyl or hydroxyl groups. 
     
     
       21. The molded composition of claim 20 in which said styrene-maleic anhydride is impact modified. 
     
     
       22. The molded composition of claim 20 in which the weight ratio of styrene-maleic anhydride copolymer to polybutylene terephthalate is from about 60:40 to about 40:60. 
     
     
       23. The molded composition of claim 20 in which said interface copolymer is present in an amount of from about 1 to about 20 parts by weight per each 100 parts by weight of the total composition, including the interface copolymer. 
     
     
       24. The molded composition of claim 20 in which said styrene-maleic anhydride copolymer has a number average molecular weight within the range of from about 50,000 to about 300,000 and contains from about 1 to about 25 weight percent maleic anhydride.